diff --git a/firmware/library/fx2rules.mk b/firmware/library/fx2rules.mk
index 0a8e44b..b64bedf 100644
--- a/firmware/library/fx2rules.mk
+++ b/firmware/library/fx2rules.mk
@@ -36,7 +36,8 @@ $(LIBFX2)/.stamp: $(wildcard $(LIBFX2)/*.c $(LIBFX2)/*.asm $(LIBFX2)/include/*.h
 -include build/*.d
 build/%.rel: %.c
 	@mkdir -p $(dir $@)
-	$(SDCC) -Wp,-MQ,$@,-MMD,build/$*.d -c -o $@ $<
+	$(SDCC) -MQ $@ -MMD -o build/$*.d $<
+	$(SDCC) -c -o $@ $<
 
 build/%.rel: %.asm
 	@mkdir -p $(dir $@)